1. Field of the Invention
The present invention relates to flowmeters for liquids utilizing the principles of pure fluid amplifiers in which a frequency is established corresponding to a particular flow, the frequency being measured to determine the flow, and the flowmeter having a wider range of usefulness than heretofore.
2. DESCRIPTION OF THE PRIOR ART
In my prior U.S. Pat. Nos. 3,640,133 and 3,855,859, flowmeters are provided in which a through passageway is provided for the flow to be measured with a fluid interaction chamber and feedback means associated with the chamber to provide an oscillation of the flow whose frequency in linearly and proportionately related to volume rate of flow. Those flowmeters were satisfactory for measuring the flow of gases in any orientation of the flowmeter but were not satisfactory for measuring liquid flow if mounted in a vertical pipe section because gases and vapors could become entrapped in the lobes of the feedback passages. The entrapped gases would influence the quality of the sensor signal by making it noisy and thus, in turn, would cause an erroneous signal output.